Back for chairs, stools, or the like



C. E. PIPP.

BACK FOR CHAIRS, STOOLS, OR THE LIKE.

APPLICATION FILED NOV: 28, 1919.

1,361,178. Patented Dec. 7, 1920.

OF GTSEGO, MICHIGAN.

CHARLES E. 'PIPP,

BACK FOR CHAIRS, STOOLS, OR THE LIKE.

Specification of Letters Patent.

Patented Dec. '7, 1920.

Application filed November 28, 1919. Serial No. 341,160.

To all whom it may concern:

Be it known that T, CrIaRLns E. Prrr, a citizen of the United States, residlng at 0tsogo, in the county or" Allegan, State of iliichigan, have invented certain new and useful Improvements in Backs for Chairs, Stools, and the like, oi which the following is a specification.

The present invention relates gen rally to the backs for chairs, stools and the like, and more particularly to backs having resilient standards which carry the back rest. The principal'objeot Of the invention is to provide a backoi the character specified which shall be simple, durable, neat in appearance and economical to manufacture. In carrying out my invention I provide a number of novel features, all of which tend to this end. Que leature consists in mounting the back rest on resilient metal strips which form the supporting standards. By the use of such strips the back cannot be twisted out of shape. and yet the necessary yielding is obtained in the direction desired. Another feature resides in the arrangement of the clamping members at the back of the back rest, so that the screws or other means by which the rest is'secured in place are hidden from view when the parts are assembled. Another feature is found in the particular construction of strap plate by which the resilient standards are secured to the seat in cooperation with the means for connecting the back rest of those standards so as to give a durable'yet yielding con sc'ruction. Other features are found in the details or construction of the clamping members and associated parts, including concave clamping jaws, jaw faces which converge outwardly when the clamping screws are not screwed down tight. in combination with a resilient outer clamping member, guiding moans, bolt locations and the like.

The various features and advantages of the invention will be more fully understood upon refrence to the following detail description, in connection with the accompanying drawing, and the scope of the invention will be particularly pointed out in the appended claims.

In said drawing: Figure 1 is a rear view of a stool provided with a back constructed in accordance with the present invention. Fig. 2 is a plan view of the same with certaiu parts shown in section, taken on a plane indicated by the line 2-2 of Fig. 1. Fig.

3 is a side elevation of the structure with certain parts shown in section taken on a plane ind'cated by the line 33 of Fig. 1. Fig. l is a detail sectional view of the clamp. ing members and associated clamping screw, taken on a plane indicated by the line H of Fig. 1, the same showing the parts in the position which they assume when the screw is screwed down tight. Fig. 5 is a similar detail view illustrating the same parts, with the screw loose, particularly illustrating the outward convergence of the jaw faces prior to the screwing down of the clamping screw. Fig. (5 is a view of the under side of the stool sea-t, illustrating particularly the strap plate into which the lower ends of the standards are inserted, and Fig. 7 is a detail'elevation of the rear of the inner clamping member, particularly illustrating one of the bolt head pockets.

Throughout these views, like characters refer to like parts.

Referring to the drawing in detail, 10, 11,

12 and 13 designate the legs of the stool to which he present invention is applied. These legs as here shown consist of strips or angle iron which are curved at their up. per ends and suitably secured to a central head 14:. This head is provided with a central opening for the passage of a threaded screw 15 which is fixed at its upper end to the collar 16 securedto the underside of the seat 17. The screw'15 is providedwith the usual retaining nut 18. All this structure is well known and forms in itself no part of the present invention. 7

The seat 17 carries on its under side a strap plate 18 which extends in close proximity to one edge of the seat, as clearly illustrated in Fig. 6. This strap is provided with portions 19 and 20 of increased width which are also spaced slightly from the under side of the seat so as to provide sockets 21, 22, for the reception of the lower ends of the resilient standards 23 and 2 1, respectively. Each of these standards consists of a horizontal portion and a vertical portion united by a curved portion, in the manner illustrated more particularly in Fig. 3. The horizontal portion enters the socket formed by the strap plate 18 and the vertical portion passes between an inner clamping member 25 and an outer clamping member 26 located at the back of the back rest 27. The portions 19 and 20 of the strap plate 18 are provided with threaded openings and setscrews 28, 29 engage these threaded openings and abut against the under sides of the horizontal portions of the standards and serve to hold them in adjusted position. Obviously these set-screws may be of any desired construction, but are here shown with flat heads for the engagement of the thumb and finger in screwing them into and out of the offset portions of the strap plate 18.

The back rest 27 is given a suitable curvature to snugly fit against the back of the user of the stool and to conform to this curvature the inner clamping member 25 is provided with offset portions 30 and 31 which are provided with curved faces which snugly fit against the rear of the rest 27. The inner clamping member 25 is secured to the rest by means of screws 32 and 33 which pass through the portions 30 and 31 into the rest 27. As clearly shown, when the parts are asembled, the screws 32 and 33 are covered by the strips 23 and 24 and are consequently out of sight. As clearly illustrated, the central portion of the inner clamping member 25 is spaced from the back of the rest 27. At points where this clamping member is offset so as to provide the portions30, 31, there are shoulders 34 and 35. These shoulders engage the edges of the standards 23 and 24 respectively when the parts are assembled. Adjacent to these shoulders the inner clamping member 25 is provided with pockets 36, 37 into which the heads of the clamping bolts 38 and 39 fit. By reason of these pockets the bolt heads are kept from rotation and con- 1 sequently the screwing down of the clamping nuts 40 and 41 upon these bolts serves to force the outer clamping member 26 against the inner clamping member. The latter nuts are provided with beaded heads for easy manipulation.

The outer clamping member 26 is similar in shape to the inner clamping member 25, but its central portion normally curves in wardly slightly, as illustrated more particularly in Fig. 5. This portion of the member 26 is also slightly yielding and produces a slight spring action, when the nuts 40 and 41 are screwed down. In other words, the screwing down of these nuts upon their bolts causes the center of the clamping member 26 to move slightly toward the clamping member 25. The member 26 is provided with offset portions 42 and 43 and shoulders 44 and 45. The latter are spaced apart so as to fit over the shoulders 34 and 35 of the clamping member 25. When the parts are loose, as illustrated in Fig. 5, the strip engaging faces on the portions 30 and 42 of the members 25 and 26 converge outwardly. The same is true of the strip engaging faces of the portions 31 and 43 of the members 25 and 26. When the nuts 40 and 41 are screwed down, the center of the outer member 26 is moved toward the member 25 and the cooperating engaging faces which bear upon the standards 23 and 24 are brought more nearly into parallelism and firmly grip the standards and hold them against displacement. It' will be noted that while this is taking place, the shoulders 34 and 35 engage the inner edges of the standards and the outward convergence of the jaw faces brings the initial pressure to bear toward the outer edge of the standards. This action prevents the standards from being forced outward, but tends to hold them in place when being secured in position.

An inspection particularly of Figs. 3, 4 and 5 will show that the jaw faces upon the outer clamping member, namely those faces of the portions 42 and 43 which engage the standards 23 and 24, are concave. This concavity is here shown as cylindrical, the axis of the cylinder lying in the direction of the length of the clamping members. Making those faces concave results in causing the upper and lower edges of the jaw faces to engage the standards. This causes a positive and definite engagement over limited areas and consequently insures a firmer and better grip than would be the case were the areas of contact larger.

It will be noted that the standards 23 and 24 are of approximately the same cross-sectional area throughout. By having strips of the form illustrated, the rest 27 may be moved forward and back with relative ease, but cannot be moved in any other direction with the same facility. These standards are preferably composed of spring steel and are given a thickness such as to provide the desired yield when the stool is in service. By giving these standards the outward curve illustrated, they do not interfere with the garments of the person using the stool. It will be noted that the sockets formed in the portions 19 and 20 of the strap plate on the under side of the seat are of sufficient size to allow some play for the horizontal portions of the standards. These standards are also located a considerable distance apart and thus contribute to the rigidity of the structure in those directions in which rigidity is required. These standards are also preferably located in parallel planes, as they are viewed in Fig. 1. On the other hand, as the parts are viewed in Fig. 3, the vertical portions lie in the same vertical plane, and the horizontal portions lie in the same horizontal plane. The use of a single strap plate 18 on the under side of the seat 17 facilitates the assembling of the parts and provides a much more rigid structure than would be possible with independent plates. As clearly shown in Fig. 6, the plate 18 is secured just inwardly of the portions 19 and 20 with a plurality of screws 4-6 and 47 which pass through openings in the plate into engagement with the seat 17. Outwardly of the portions 19 and 20 single screws 48 and 49 secure the strap to the seat.

Throughout the construction illustrated, all the parts are composed of metal except the seat 17 and the back rest 27. The latter are preferably composed of wood, although, of course, they may be composed of metal also, if desired. It will be noted that the offset portions 30, 31, 42 and 43 of the members 25 and 26 serve as jaws to grip the standards 23 and 2% when the nuts 40 and ll are screwed home.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A device of the class described comprising a seat, two flat resilient metal strips forming standards extending upward from said seat, a transverse back rest, an elongated inner clamping member having clamping jaws at its outer ends, securing means extending through openings in said jaws to secure said member to said rest, an outer clamping member fitting upon said inner clamping member and having cooperating jaws at its outer ends, and means for drawing said clamping members toward each other to clamp said jaws upon said strips with said securing means covered by said strips and out of sight.

2. A device of the class described comprising a seat, two fiat resilient metal strips forming standards extending upward from said seat, a back rest, an elongated inner clamping member secured to and extending lengthwise of said rest and having clamping jaws at its outer ends, an outer clamping member fitting upon said inner clamping member and having cooperating jaws at its outer ends, certain of the jaws of said clamping members having concave engaging surfaces for gripping said strips more securely, said concave surfaces having their axes of curvature extending transversely of said strips, and means for causing said clamping jaws to firmly clamp said strips, one strip between each cooperating pair of aws.

3. A device of the class described, comprising a seat, two flat resilient metal strips forming standards extending upward from said seat, a back rest, an elongated inner clamping member secured to and extending lengthwise of said rest and having offset portionsat its ends forming clamping jaws, a similarly shaped outer clamping member having similar offset portions at its ends forming clamping jaws for cooperation with the jaws on said inner member, said pairs of jaws being arranged to engage the faces and inner edges of the upper ends of said standards respectively, bolts extending through openings in said clamping members just inward of said jaws, and nuts upon said bolts for moving said members and jaws into and out of clamping position.

4:. A device of the class described com-- prising a seat, two fiat resilient metal strips forming standards extending upward from said seat, a back rest, an elongated inner clamping member secured to and extending lengthwise of said rest and having offset portions at its ends forming strip-clamping jaws, a similarly shaped outer clamping member having similar offset portions at its ends forming strip-clamping jaws for cooperation with the jaws on said inner clamping member, bolts extending through openings in said clamping members and having heads resting in pockets in said inner clamping member just inward of said jaws, and nuts on said bolts bearing against said outer clamping member and operative to move said clamping members and jaws into and out of clamping position, the portion of said outer clamping member between said bolts being slightly resilient.

5. A device of the class described comprising a seat, two flat resilient metal strips forming standards extending upward from said seat, a back rest, an elongated inner clamping member secured to said rest and having clamping jaws at its ends, a similarly shaped outer clamping member fitting upon said inner clamping member and having clamping jaws at its end for cooperation with the jaws on said inner clamping mem ber, bolts extending through openings in said clampingmembers, and nuts upon said bolts for moving said members and jaws into and out of clamping position, the portion of the outer clamping member between said bolts being resilient enough to yield slightly under the strain applied when said nuts are screwed down, and the faces on each pair of cooperating jaws converging outward before said nuts are screwed down, whereby a pressure is applied to all portions of said strips lying between said jaws when said nuts are screwed down.

6. A device of the class described comprising a seat, two flat resilient metal strips forming standards extending upward from said seat, a back rest, an inner clamping member secured to said rest and having its ends offset toward said rest, one face of each offset portion bearing against said rest, the other face of said offset portion constituting a jaw face, said member having shoulders just inward of said jaw faces, a similarly shaped outer clamping member having its ends offset toward said inner clamping member, the inner face of each offset portion constituting a aw face for cooperating with the associated jaw face on said inner clamping member, said outer clamping member having shoulders just in- Ward of its jaw faces, the shoulders on said inner and outer clamping members coacting to guide said outer member upon said inner member, and bolts and nuts for drawing said members together.

7. A device of the class described comprising a seat, two flat resilient metal strips forming standards extending upward from said seat, a back rest, an inner clamping member secured to said rest having shoulders and clamping jaws at its ends, a cooperating outer clamping member having jaws at its ends for cooperating with the jaws on said inner clamping member, bolts extending through openings in said clamping members, and nuts upon said bolts for moving said members and jaws into and out of clamping position, the faces of opposing jaws and the adjacent shoulder on said inner clamping member cooperating to engage and hold said standards, the opposing jaw faces converging outward from the shoulder in each instance before said nuts are screwed up tight. 7

8. A device of the class described comprising a seat, flat strip standards extending upward therefrom, a back rest, inner and outer clamping members for securing said rest to said standards, and means for actuating said members into and out of clamping position, said members having at each end an inner shoulder, against which the inner edge of the standard abuts and converging outward jaw faces for engaging the fiat faces of the standard when said members are in clamping position, said jaw faces being outwardly convergent before said clamping members are moved into tight clamping engagement with said standards.

In testimony whereof I hereunto subscribe my name this 17 day of November, A. D. 1919.

CHARLES E. PIPP. 

